


Earth's Mightiest Monster

by Ononymous



Series: DCUU - DC Underground Universe [2]
Category: Captain Marvel (DC), DCU (Comics), Undertale (Video Game)
Genre: Crossover, Gen, Post-Undertale Pacifist Route
Language: English
Status: Completed
Published: 2017-07-31
Updated: 2017-07-31
Packaged: 2018-12-09 06:06:10
Rating: General Audiences
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 4,529
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/11663181
Author URL: https://archiveofourown.org/users/Ononymous/pseuds/Ononymous
Summary: In spite of the promise he made to Superman, the day to day grind of his life has been really hard to bare. Fortunately another hero is willing to offer some help.





	Earth's Mightiest Monster

"My child!"

His head jerked up, ears flopping about, and gently bumped his head against the trunk of the tree he had laid against. Fortunately it didn't hurt. His eyes squinted as they adjusted to the rays of sunlight pouring through the filter the leaves provided.

"My child, dinner is ready!"

"Coming, Mom!"

Cheerful, he got to his feet, ran out from under the tree and along the sunlit field. Then he was in a small forest, and running up a rocky hillside, and alongside a stream in a valley. Before very long he had reached the cavern entrance and returned to New Home. He dashed into the house, turning left sharply to find his parents already at the table. The complimentary scents of cinnamon and butterscotch filled his nostrils.

"It smells great, Mom!"

She smiled warmly at him. "I am sure it does, but you have to eat the main course first. Yours is over here."

"I helped select the ingredients." said his father, stroking his golden beard with pride. "Your mother may be the better cook, but I can still recognise freshness when I see it."

He clambered into his seat, where a large platter was covered. Feeling absolutely ravenous, he lifted the lid.

"Oh boy!"

A large mound of soil lay on the platter, dark and moist. Licking his lips, he placed it on the ground, and buried his feet in it up to his ankles. As he absorbed the nutrients, he rubbed his belly in satisfaction. Absently his head turned towards the sunlight beaming in through the window, as he looked over the great dark city covered by a rocky roof.

"This is delicious, definitely high-nitrogen! You always know where to find the best soil, Dad."

His father chuckled softly.

"How was school today, my child?"

"It was great! Mister Kent brought in a cloud to teach us about it, and I put my hand in it, and it was all wet! They really are made of water!"

"I wish I could've seen it."

The three of them started at the pale and clammy child with flushed cheeks who sat quietly at the table, with a trickle of blood at the corner of their mouth.

"Now child, we still do not know why you are ill. Once we discover the cause we can get the correct medicine, you will get better, and you can go to school with your brother."

"That'd be nice. Could someone please pass the buttercups?"

Careful not to spill his dinner, he leaned over and shoved the bowl of yellow flowers so it slid over to his best friend.

"Thanks. I knew I could count on you."

He fiddled with his ear. "Aw, shucks."

They took one and chewed quietly on it, making gargling and choking noises as they forced themselves to swallow. The King and Queen regarded them kindly.

"At least you still have a good appetite." the King mused in appreciation. With a glint of mischief in his eye, he plucked another flower from the bowl and ate it himself, coughing and spluttering as he too forced it down.

"We have discussed this before, dear. Leave the children's meals alone."

"Sorry, honey."

"Now my child, have you finished?"

"Yep! It was great!"

She smiled again. "Very good. Please go and wash your feet before pie."

"Okay!"

Taking care to extract his feet from the soil without a mess, he started to run out of the kitchen. But a rush of affection seized him. He changed course, and leapt into his father's arms. Despite now looking bedraggled as he digested his flower, with sunken shadowed eyes and matted fur, he embraced the sudden hug as tightly as ever. And then his mother joined the fray. It felt good to be hugged like this. So tightly he couldn't move his arms or legs.

So tightly he couldn't feel his arms or legs.

So tightly it felt like he wasn't being hugged at all.

He woke up. For a moment he thought he could still feel the warmth, but he quickly realised it had never been there. Only the ache remained. He could feel tears starting to well up, but this new phenomenon was overridden by a familiar stab of anger.

"Dammit, not again!"

The flower had been sleeping. He hadn't needed to, not for a long time, but he found it helped the time go by. A break from himself was a respite. But lately this was proving to be less of a comfort. His reaction to the dreams was shifting, and he was pretty sure he knew why.

There were parts of the dream that once upon a time he would have found disturbing or outright horrifying, racked with guilt for what he did. But he could only regard those parts with sadness. What was gnawing at him lately was how damn happy his dream counterpart was, and how he could pretend he felt that way for maybe a second after he woke. And then the reality of that void where the joy should be sunk in.

And his dream self _was_ happy. He was sure of it. It wasn't some made up idea of what his dreams thought happiness was. He had been told of the miracle inside him, but it was only in the last month he could feel it. Yet it still wouldn't share itself with him, or help him in any way. It wasn't strong enough. And yet it tapped into his dreams and let another him enjoy a life _he_ couldn't have.

These dreams were becoming torture. He was beginning to prefer the numbness that true soullessness had provided. But still, he had promised. He had even understood why that day. But it had gotten harder to do since then. Especially as the soul was not giving any hints about when it would be finished, or if it would even do anything when it was. The base impulses he had allowed to run rampant for most of his current life were getting pretty insistent that maybe all this waiting was for nothing, while his atrophied sense of patience, despite being bolstered by the promised reward at the end, found it hard to hold the line.

And without warning, another flush of anger made up his mind.

"I'm sick of it! I'll drag him back here and make him fix me! And if he can't, maybe I'll just find something else to do! Who needs a soul if it's gonna taunt me?!"

Shouting it aloud seemed to vent a sliver of his frustration, but most of it was poured into attacking a small recess on the wall. Two large vines whipped at it. It paid off, as a chunk of the wall crumbled.

The frustration had been briefly quelled by the outburst, and he momentarily forgot his reason for it. A glint of silver reminded him however. He viewed his prize blankly for a moment. A watch with a conspicuous red button along the side.

A voice that should have felt like his was telling him to leave it alone, that he would be fine if he held out a bit longer. But he was too agitated, and figured he might as well. One of his vines carefully picked it up and-

A streaky red blur zoomed across his field of vision, and the vine was suddenly empty.

"Huh?! What the-"

"Are you sure you want to do that?"

He twisted round. A tall figure stood with his back to him, examining the watch. Dressed in red rather than blue, but familiar jet black hair.

" _You!_ "

His frustration boiling at being robbed, he acted on instinct. Half a dozen white bullets appeared and zoomed into the newcomer's back. They struck on target, but vanished with a pathetic 'plink' noise. He didn't react at all.

"What?! Last time those sent you flying!"

"Sent _me_ flying?" the newcomer said pleasantly. "Oh golly, you think I'm Clark! Yeah, that would probably hurt him, being magic and all. I'm better at dealing with that."

"Wait. You know him?"

"Oh sure, we're friends."

He finally turned around. He was every bit as tall as Superman, if slightly more stocky. His hair was looser and more curly. His face slightly rounder, and somehow even friendlier than Superman's. His red outfit was adorned with a yellow thunderbolt on his chest and a white half-cape on his left shoulder.

"Howdy. I'm Captain Marvel! What's your name?"

The flower regarded him suspiciously. That greeting irritated him.

"You didn't just wander in here by accident. You came to see me, didn't you?" Marvel shrugged. "Then I bet he told you everything."

"Sure. But I wanted to hear it from you."

"I..." he glowered at this unexpected interview, "I'm between names right now, okay?"

"Really? That's surprising, the way Clark put it you were happy to be called-"

" **HEY!** Feelings change, okay? A lot in my case. They go away and give me no reason to stick with it. I mean I've been trying to stick with it, but it's hard to see the point. Now give me my watch back, you idiot! It's mine, he gave it to me!"

"Yeah, he did. It won't do you much good though. He's not available."

"What? Why not?!"

"The report's a bit sketchy. Some of it seems to suggest his powers have changed to be completely different. Other parts have him trapped on another world. And the last part suggested he's dead. Again. Whatever's happened, we haven't been able to contact him. It happens now and then, I'm sure he'll be fine in a couple of weeks."

The flower sneered at him. "And he left you to clean up after him? He screws up and he hasn't even got the guts to say sorry and-"

"Nah. I came here myself. Nobody knows I'm here. I've been coming for a while."

"And why?" he spat. "Did he tell you what I tried to do when we first met? Afraid I'm gonna have a relapse and go on a rampage or something? It's tempting."

It felt as close to good as he could feel to bluster about it, but that voice that didn't quite fit him was protesting fiercely in a way it hadn't in years. He ignored it.

Captain Marvel raised an eyebrow. "Why are you so mad at him anyway? How has he screwed up?"

"Because... because..."

He had been preparing to tear into Superman some more, but that other voice managed to force a bit of honesty into his agitation.

"Because this is really hard!"

He stared daggers at his guest, who merely returned a polite and curious smile.

"I had it all figured out! Stay here where I couldn't hurt anybody, where I wouldn't break anyone's heart, and then let the numbness soothe it. But then _he_ comes along with that stupid smile and spins a story about not giving up, and then he thinks taking me on a trip will cheer me up and then he tells me what I've got growing inside me and like a stupid idiot I promise to have _hope_. Well I've hoped for months, and nothing's happened! Nothing except these stupid dreams and then I wake up and it's like I'm teasing myself with what I can't have! Why'd he do that to me? It... it hurts to hope."

His yellow head bowed towards the ground, temporarily expunged of the venom that had seized him. Captain Marvel breathed softly and looked towards the hole in the cavern ceiling.

"Yep. That sounds about right. And that's why I'm here."

"Why are you here?" The anger had boiled away, leaving only coldness.

"Well the thing about Clark is that he's really good at riling you up. You see him do amazing things that most people can't, and he gets you to look inside yourself and find that little bit of something that lets you push a little harder, hold on a little longer. Even if you're not lifting a car, he makes you think you can do anything. I mean, he certainly did that number on you, didn't he?"

The flower narrowed his eyes, and reluctantly nodded.

"And that's a good thing. He's great at getting us to see the best of ourselves. However, and I hate to criticise him, there's something he can overlook with his big picture stirring speeches."

"Really?" piped up the flower. He was genuinely curious, partly to have some dirt on Superman. "What's that?"

"Sometimes he doesn't get kids."

"Huh?"

"Not that he's bad with kids or anything. He babysits for his friends, and he never gets trouble, even from the unusual ones. But sometimes he forgets how children think and feel. What he asked you to do was never going to be easy. You've done really well so far, but staying on your own hasn't made it any easier. He wants to respect your solitude while you figure yourself out, but that's not always the best approach with kids. Sometimes they need someone to talk to. You don't have to do it alone."

"And you get kids, is that it?" the voice rang with scepticism. "You have a special insight that the guy who calls himself the strongest in the world doesn't?"

"Yes, actually." he replied sincerely. "Also, I can do this."

He tapped an index finger to his temple. His eyes turned golden and sparked with electricity. He looked directly at the flowerbed, whose most active occupant felt like he was being examined inside and out. Before he could complain, the golden eyes became blue again.

"It's coming along nicely." said Marvel. "I've been checking on your soul every now and then. It's almost as big as your Dad's!"

"My- You mean Asgore? I don't really- Hey, when did you meet him?!"

"Oh, the League held a dinner a while back, and they were guests. They're really nice. I took a peek at their souls while they were being seated, so I knew what to expect with you."

"'They'? Oh, you mean Toriel was there too?"

"Well, yeah. Hey, why are you calling them by their names? Aren't they your-"

"Stop it." he snarled. "Stop talking about that life like it's mine. It hasn't been for a long time."

"But it can be again. Nobody could have foreseen this, but all the circumstances have built up to give you a unique opportunity. Why are you distancing yourself from it? Are you afraid that even with a soul you won't be able to go back to them?"

"No, you idiot, I'm afraid that I will!"

He was surprised at himself. Until he had said the words he hadn't really thought about how he felt about having a home again. Even with Superman the focus was on merely having a soul, not what he'd do with it. And the idea scared him? He didn't understand. Marvel seemed to be connecting dots however.

"I understand." he said kindly, as if taunting him with knowledge he couldn't have. "It's been a long time, you don't know what'll happen. And you don't want to face them after what you did. But it won't matter to them. Sometimes people don't appreciate their family until it's too late. You're getting a second chance few people do. Don't let it pass you by. For them as much as you."

The earnestness in his voice gave the flower pause. He was speaking from experience here.

"But..." the voice was flat and toneless, "I don't deserve it. Even if I could feel I'd tell you that. Not after all I did."

"Well from what I can tell, you're getting that chance anyway, no matter what you do. Might as well make the most of it, maybe use it to make up for what you did. And hey," his smile grew, "maybe we can see how you _really_ feel today."

"Huh? What are you talking about-?"

But Captain Marvel suddenly looked towards the corridor which served as the cavern's exit.

"Can you hear footsteps?"

He turned that way too. Sure enough, two sets of footsteps were slowly getting louder.

"Who could... wait, my dream. That means... it was today. _Today?!_ No, not them, I'm not ready!"

He turned back and looked up at Marvel again. His beady eyes were wide with panic.

"Look buddy, you wanna be my friend or whatever, fine. First friendly gesture, get me out of here! I don't want to see them!"

He didn't resist as vines wrapped around his arm. Once his passenger was secure, he silently lifted off the ground and ascended through the hole.

"Wait," the flower whispered, "I wanna see."

So they looked down at the flowerbed. If you hadn't known about the flower's outburst earlier, it wasn't obvious anybody had been there, which was just as well.

The owners of the footsteps made themselves known. Two figures, taller than humans, with white fur and equally white horns. The taller one also had a golden mane of hair and beard. They looked utterly stoic as they approached the flowerbed, but there were tears in the King's eyes. They stood side by side, focused on the flowers. Then they each took something out of their pockets. Toriel laid a chocolate bar among the flowers, and Asgore added a picture of a moonlit night, blanketed in stars. This tribute paid, Toriel finally allowed herself to shed tears, while Asgore sobbed silently. Before long, he looked over to Toriel, but she ignored him, focused solely on the tokens of love. But eventually she relented, and rest a hand on the small of his back. Asgore seemed to know this was the best he could hope for, and nodded to the cavern at large. And then they turned, walking slowly away, together but still apart. The interlopers regarded the scene for a while.

"Huh. That's strange." said Marvel.

"What's strange?" His voice had a quaver he hadn't intended.

"Well, it's just that I've never seen a flower cry before."

A moment's shock, and then he brought a vine to his lower petals. Sure enough they felt wet. And at this he became acutely aware of the ache he had woken with. And how it felt different.

"I... I miss them... but I hurt them so badly... it hurts, I don't want-"

"Hey, it's okay." A warm hand rested on the back of his head for a moment. Instead of comforting him, it spurred him to adopt a face of determined blankness, ignoring the tears still on his face.

"Okay," he said flatly. "They're gone. Bring me back down now."

"Nah."

"What?"

"Nah. We're friends now. You said so yourself! I gotta do more than that for my friend."

"What are you, deaf? I don't want-"

But Captain Marvel strode out of the cave with complete confidence. Both of them blinked in the sunlight.

"What now, a free flight? Superman did that already, and that was when I could appreciate it. It's not gonna make me feel better."

"Yeah, I know. I've something else in mind."

With a woosh he took off, rose to around halfway up Mount Ebott, and shot away. There were no fancy twists and turns this time. This was an express trip. If nothing else, he could begrudgingly appreciate the change in scenery from sitting in a cave. He noted the city from his last trip, and before long they were at the far side of it. After a surprisingly short time, they were descending again. There was a cluster of trees on the outskirts of what looked like a suburb town of the city, near a large building like a school.

"Did you enjoy the ride?"

"Eh, Superman did it better."

Marvel chuckled as he extended his vine-wrapped hand towards the ground. Cautiously, his passenger planted himself in the grass.

"So what are we doing here? Are you gonna win me over with another moving speech?"

"Not really. The best speech in the world does nothing if you aren't equipped to listen to it. Sometimes you just have to act. I've been thinking how to help you, and I think I know."

Without warning he reached a hand onto the stem. A vine smacked it back as his quarry jerked back a few feet.

"Hey! Don't do that!"

"It's okay, I'm just-"

"I don't care! Don't you get it, idiot, I _can't_ care!"

"That's not even true anymore and you know it, As-"

" _ **SHUT UP!**_ Don't call me that! Don't think you can just waltz in and make everything better with your electric hands or whatever. I never asked to care again, to feel bad for what I did, what I'm doing to them! Why should I feel that without any benefits? Maybe I don't _want_ to care with all that on my tally, y'ever think of that? Maybe numbness is better for me!"

"That's not true-"

He wasn't listening. Not to the man in red, and not to the voice screaming at him in his head. Determined to ride out this temper for as long as it lasted, he dashed away from Marvel. Surprisingly fast for a plant moving through soil. He glanced back to make sure he couldn't see any red, but as he turned back red blocked his vision.

"Leave me alone!"

A vine, much larger than any he had used that day, smacked Captain Marvel into a nearby tree.

"Holy moley, you pack a punch-"

He was speeding away again, ready to strike at anything red in his path. He was rewarded for this vigilance by narrowly dodging a bolt of lightning, and turning around on instinct. And that's when he realised a hand was touching his stem again. He raised a vine to attack its owner as-

" _ **SHAZAM!**_ "

There was a crack of thunder and a blinding bolt of lightning. The outstretched vine vanished. A cloud of smoke lingered.

Eventually they could see each other as the smoke cleared. A young human boy with the same eyes as Captain Marvel, looking into the emerald eyes of a child covered in white fur, one hand still on his brand new shoulder. Quite frozen and unsure what to do.

"Hey there. Let's try this again. My name's Billy. Billy Batson. What's your name?"

But instead of a response came trembling. Billy could see it. Feelings that had fought tooth and nail for a split second on the flower's face now flowed freely. The trembling became shaking.

"...no no no, Clark, I tried, I'm so sorry, Mom, Dad, Chara, I should have..."

The Wisdom of Solomon nudged him, and Billy pulled the child into a hug. That did it. The muttering was replaced with sobbing. Shame at lashing out, and relief that he'd stopped. Guilt for what he had done long ago, and what he was still doing and what this was doing to those he cared for. Because he did care for them now.

"Hey, hey, it's alright," said Billy softly, "no harm, no foul, right? Didn't quite catch your name though."

"...A-Asriel..."

The name sprang from his mouth unchallenged, and in that moment he couldn't comprehend why he refused to take ownership of it. He even let a smile form on his mouth as they continued to hug tightly. Eventually Billy let him go, and he took the opportunity to revel in wonder at having hands and feet again, and not wanting in the slightest to bury them in soil for dinner.

"Is this... am I me? Will I stay like this?"

Billy's own smile faded. "No. This is temporary, maybe a day or so. I might have figured out how to make it permanent, but I didn't want to risk messing up your soul. In any case, I thought you needed a break. To remind you why you promised Clark not to give up."

Asriel regarded this information stoically enough. "And for my soul... how long do you think it will be?"

"Hard to say. Judging by your parents' souls and how fast yours is growing, maybe another month or two."

"Well, that's not so bad!" His muzzle split into a true smile. "I can wait."

"And you're okay with... your other feelings?"

It was the turn of Asriel's smile to fade. "I don't know if I ever can be. But it's like you said, it's coming whether I like it or not. I just have to get ready. I think I can worry about that another day."

"That's the spirit!" He gave a wink that reminded Asriel of Clark.

"Why here, though? You could have changed me in the cavern."

"Ah, well that was only the first part of the plan," said Billy slyly, "come this way to see the conclusion. Wow, your hand's even fluffier than your Dad's!"

The two children made their way through the thicket, which thinned quickly. They were now at the edge of a tarmac surface, beyond which was the school-like building.

"Hey, it's Billy!"

A small group of human children converged on him.

"Hey Billy!"

"How's the radio job?"

"It's cool you don't forget about other orphans."

"Who's that...?"

"Calm down everyone! Now you remember I was talking to you the other day about a friend that might need a few more? This is him. Be nice to him, okay?"

Even as a child Billy was tall, something Asriel was using to his advantage as he suddenly felt half a dozen sets of eyes converge on him.

"Wow, he's a monster! That's cool!"

"He looks nice!"

"Hello."

One of the children had broken away from the pack and approached him, and stopped short with an outreached hand. Asriel looked at their blank face and for a moment had a stab of recognition, before realising they were somebody else.

"My name's Frisk. What's yours?"

They gave a small smile that seemed to bolster his courage. He took their hand and shook with enthusiasm.

"'Frisk'? That's a nice name. I'm Asriel. H-howdy!"

His confidence had ramped up as the conversation continued. The other kids looked jealous at Frisk making first contact.

"I think the monsters are nice. I was near Mount Ebott a few months ago, and I saw Superman fly there, and then it was all over the news the next day. I see them on the street sometimes, but I haven't talked to any of them yet. I like the skeletons, I think they're funny."

"Yeah, Papyrus is great." said Asriel carelessly, having only decided this a moment ago.

"Oh, do you know them?"

"Kind of. I don't know if they know me."

"Maybe we could meet them all together?"

"I'd like that! Only, I'm very busy for, uh, a month or two. But we can do it then."

"Sounds great!"

"Come on Frisk, don't hog him!"

"Hey!" yelled Billy. "Don't crowd him!"

"It's okay, Billy," said Asriel, "and thanks for taking me here. It's been a long time."

After concluding the exchange of names, a game of kickball was agreed on. When Billy would take Asriel home later that day, he'd have quite the story to tell Superman when he was ready to call for him.

**Author's Note:**

> Original draft: https://pastebin.com/ZDEKqARh
> 
> Let me know what you think, and thanks for reading!


End file.
